A: All great cities—ambitious, but doable. I’ve never been to Amsterdam (just great stories from fellow travelers) but I’ve lived in London and Florence, and visit Barcelona regularly. The first thing to consider is amount of travel time. I generally prefer to travel at a slower pace, moving from a city after a minimum of four days. A traveler tends to cover more sightseeing ground and has more food/drink/music/nightlife opportunities with more time. So try to spend larger chunks of time in each city, if you can. Moving from city to city isn’t too complicated—it just takes lots of trip planning.
Here’s a (quick) run-down of what I’d do:
Fly from the U.S. to Dublin (if you can, try for March 17 on St. Patrick’s Day). Dublin is one of Europe’s most expensive cities, so try renting an apartment to save money on a hostel while you’re here (try http://www.airbnb.com/). From Dublin, fly Ryan Air (http://www.ryanair.com) to one of London’s three airports: Gatwick Heathrow, or Stansted. While you’re in London, here’s a few of my favorite free things to do. If you can, try to stay at least a week because there’s so much to see. Definitely check out the London Eye (tickets are about 20 GPB) a Broadway show (buy tickets at Leicester Square) and all the free museums.
When you’re ready to move on to Amsterdam, fly from London. I don’t know much about the city because I’ve never been there, but the Travel Channel has covered it pretty extensively. Check it out: http://www.travelchannel.com/topics/amsterdam/index.html
From Amsterdam, fly to Florence. Florence is one of my favorite European cities, and if you’re at all an art buff, food lover, or wine-o, it’s the city for you. Here’s what to see and do when you get there.
Florence (or Rome) should have cheap flights to Barcelona—one of Spain’s coolest cities because it has Parc Guell, Sagrada Familia, and of course, the ocean. Here’s what to see and do there.
If you plan to fly into Dublin and out of Barcelona, you can probably find cheap tickets since they’re both larger Euro-travel hubs to the states. Otherwise, I’d book one-way tickets (quite easy to do on European airlines, since most tickets are two-part go/return anyways). This way, you can determine the cheapest days to fly and the duration you want to stay in each city. Traveling in summer will be warmer, but way more expensive since it’s high season. Traveling in winter will be cheaper, but some things may not be open and if you’re looking for fun nightlife summer is generally better across the board.
Ryan Air http://www.ryanair.com
Easy Jet http://www.easyjet.com